Review: MiBoxer C2-3000 2 Port Battery Charger

Back in the 1960s, my dad worked for Westinghouse, and they gave him a van load of rechargeable batteries. He put them in all of our devices, so I knew a childhood where everything was rechargeable decades before everyone else did.

But people still buy disposable batteries, which makes me sad, because the technology has been around for too long to waste your money on something you only get one use out of, instead of modern cells that can be recharged 1,000 times or more. Why buy 1,000 batteries when you can recharge just one?

Part of the problem now is that there’s so many different types battery chemistry and formats to worry about. So I’ve been happy to see the slew of smart chargers that have popped up over the last few years. These types of chargers can pretty much charge anything rechargeable that fits in the charging slot. I can give a family member a mixture of lithium-ion and AA rechargeable flashlights without worrying about them burning their house down!

Product Description

Price: 20 bucks online?

The C2-3000 is a 2 slot, analyzing charger that uses a USB charging interface, with its included cable. It claims to charge pretty much any lithium-ion, NiMh or NiCd cell that fits in the charging slot. It’s informational display tracks capacity, voltage, internal resistance, charge rate and estimated remaining time.

Official Specs (From MiBoxer)

Initial Impressions

Overall, good. Out of the box, it almost looks like a re-branded Nitecore charger or one from the big brands. The Chinese don’t put the same focus on brand recognition as other countries, so it’s always a good guessing game figuring out where something is made, and who made it.

MiBoxer chose an interesting power configuration. The unit comes with a DC plug on one end of the supplied cable, but the other end is a standard USB cable end. I would’ve preferred a standard mini or micro USB on the other end, but it’s not a huge deal unless you lose the cable. Don’t lose the cable!

The included 12 V car adapter is a nice touch. That’s really the good thing about USB smart chargers: you can charge your batteries anywhere. I have a couple large USB power packs I built myself, which makes it handy to charge flashlight cells from a portable pack.

The informational display is impressive. Extra points for showing the internal resistance and estimated time remaining.

Build Quality

Overall, good. My review sample seems to be well built. The plastic housing is as thick as I think it should be and the spring loaded contacts look durable enough. The back lit display is a nice touch and well mounted. The charge cable is thicker than most of my USB cables and definitely appreciated, though it is a non-standard cable.

All things considered this unit seems well built for a budget charger, which I assume is selling in the 20 dollar range.

Fit & Finish

Overall, good. The single button on the unit looks a little cheap, but reasonable for a charger in this price range, and just like my other chargers. It’d be nice to see something more durable like the rubber coated switches with the anodized rings on some of my flashlights.

There’s not really much to pick on: The information on the backlit display is extremely crisp, though the back light seems a little on the bright side. The cells fit well into the charging slots. The sliding, spring-loaded contacts slide well.

The charging cable has a secure fit, which is good because it’s a non-standard USB cable. As far as fit & finish goes, this could easily pass for one of the bigger brands.

Features

The C2-3000 is a two slot charger that can charge pretty much any rechargeable cell that fits in one of its slots. With a USB interface, it can charge cells from a wall charger, included car charger, laptop, desktop, or power pack–basically anything with a USB port that puts out 5 volts.

There’s a button on the charger that switches the display between slot #1 and slot #2, and the display shows lots of information:

Estimated time remaining

Measured capacity

Internal Resistance

Current Voltage

Charge Rate

Above I’m charging two Samsung 18650 (3,000 mAh) lithium-ion cells

There’s no special test modes, which seem to be on their 4 slot model.

Charge Rate

The achilles’ heel of any USB charger is that they tend to be really conservative on charge rate, which makes sense because the charger doesn’t know the quality of the USB power source it’s being plugged into.

Because of the lower charge rate, it can take 8 (or more) hours to charge some of the higher capacity lithium-ion cells like the 18650 or 25650. So anyone looking at a USB charger to charge lithium-ion cells should take this knowledge into account.

When I first plugged this charger in and put in a Panasonic 18650 3400 mAh cell, it started out at 100 mAh, which is extremely low.

But luckily the charger is just really cautious and will gradually bump the charge rate up. I did a little video and it was still at 200 mAh, but I checked an hour later and it was up to 550 mAh, which is about as high as most USB chargers go.

Usability

This is a fun charger, and the only one I have which measures internal resistance. It seems to charge a little faster than other USB chargers I’ve owned. Maybe even given its 550 mAh charge output, which leads me to suspect it might be charging a little higher than its reported output.

The estimated time remaining is also nice. I’m a busy guy, and we’re all used to our other devices giving us an estimate, even if we know it’s just an estimate.

Wait, 9 hours?

Doesn’t seem to have any problems mixing battery chemistries on the same charge

Conclusions

If you use high capacity lithium-ion cells on a daily basis, you probably want a 2 amp wall charger. But if you use these cells every day, you probably already know this.

If you use lots of different cells once in a while like most people, then USB chargers like this are nice because they give you lots of options for charging, with a sacrifice in charging rate. And this seems like a good USB charger, even if I’ve never heard of the brand. This one shows how smart these budget chargers are getting, and I really like the internal resistance display, which gives you an idea of how much life the cell has left in it.

It’s still a good option for me as a 2nd charger, because I like to build my own USB power packs, and it’s very appealing being able to charge all my cells from a power pack or my truck in a pinch. I always throw a USB charger like this one in the truck for camping and long road trips.

For this reason, I think these types of chargers are good for survival bags and living off the grid. Combined with a power pack and USB solar panel like the one I have, I can charge AA and AAA cells indefinitely in an emergency, as well as all my lithium-ion cells. Chargers like this one plug straight into the solar panel!